Multistep Synthesis of a Radiolabeled Imaging Probe Using Integrated Microfluidics

Abstract

Microreactor technology has shown potential for optimizing synthetic efficiency, particularly in preparing sensitive compounds. We achieved the synthesis of an [ ¹⁸ F]fluoride-radiolabeled molecular imaging probe, 2-deoxy-2-[ ¹⁸ F]fluoro- d -glucose ([ ¹⁸ F]FDG), in an integrated microfluidic device. Five sequential processes—[ ¹⁸ F]fluoride concentration, water evaporation, radiofluorination, solvent exchange, and hydrolytic deprotection—proceeded with high radio-chemical yield and purity and with shorter synthesis time relative to conventional automated synthesis. Multiple doses of [ ¹⁸ F]FDG for positron emission tomography imaging studies in mice were prepared. These results, which constitute a proof of principle for automated multistep syntheses at the nanogram to microgram scale, could be generalized to a range of radiolabeled substrates.